Where Does the Smell of Rain Come From?

Get out have quite a pause for your steps for a minute and imagine the scent of the rain. One could almost smell it. Before the precipitation appears, the breeze smells vibrant and sweet soon the tiny droplets start descending towards the dry land followed by the scent of fresh ground and grass, and the moist humid fragrance lingers afterwards.



In the 1964 essay ‘Nature of Argillaceous Odour’ published in Nature’s journals the word, Petrichor was coined by two Australian scientists Isabel Joy Bear and Richard Thomas. The word “stone” was derived from Greek Petros meaning stones and Ichor implying “the fluid which streams into the veins of the gods.

During their research, the rocks that had been subjected to warm and dry conditions were distilled to expose the odor of a yellow-colored oil that was concealed in the rocks and soils. The origin of this oil is a mixture of oils that are secreted from plants under dry weather and chemicals released by soil-dwelling bacteria.

How Do Rain Gets Its Smell?

Certain compounds like ozone, Geosmin, and plant soils also hold a key role in the scent of the rain.

The first, the “clean” odor is induced by ozone, particularly after a major downpour. The dense earthy scent is the strongest following a dry spell, or particularly high rains, ozone (scientifically recognized to be have been trioxide since it comprises of 3 atoms with oxygen), which has a very sharp odor, which is widely classified as chlorinated.

The second scent is the outcome of a relatively frequent bacterium in the soil.  During exceptionally drought periods several microbes, particularly classified Streptomyces, generates spores. The further the soil stays loose, the more spores frequently multiply. However, the scent doesn’t correspond with the spores. It is rather due to a chemical excreted during the processing of the so-called “Geosmine” spores.

The third source of the scent of the soil is primarily driven by oils naturally secreted by wild varieties of plants. These oils gather and discharge certain chemicals in the environment (usually in combination with Geosmine) into the atmosphere throughout rain, triggering a recognizable and enticing scent.

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